Conductivity sensors normally comprise a sensor element that is immersed in the medium to be measured. In order to determine the electrolytic conductivity of the medium, the resistance or conductance of the measuring path in the medium is determined. If the cell constant is known, the conductivity of the measuring medium can then be determined. The sensor element is connected by a line or a cable to a measuring transducer, by means of which the conductivity can be determined using the measured data.
The sensor element, in turn, is connected to a process connection. This combination of the sensor element and process connection will be termed a “sensor” in the following. The process connection serves to connect the sensor to a container in which the medium to be measured is located.
At the connecting site between the sensor element and process connection, corners, edges, burs, and other unevennesses arise from the multi-part construction with seals between the process connection and the sensor element. Dirt, dust, medium, etc., can adhere to these sites. Consequently, such a sensor is unsuitable for hygienic requirements.
German patent application no. DE 102014117685 A1 describes a method for producing a conductivity sensor. The sensor comprises a process connection and a sensor element. The method comprises the following steps.
Initially, a first region of the sensor element is adapted to a first region of the process connection, so that, when the first region of the sensor element is introduced into the first region of the process connection, a second region of the sensor element projects beyond the process connection. Then, both first regions are provided with an adhesive. Subsequently, the first region of the sensor element is introduced into the first region of the process connection, so that the adhesive is arranged in a gap between the first region of the sensor element and the first region of the process connection.
A disadvantage of such a solution is that the adhesive effect of the adhesive attenuates over time.